Abstract:

To inhibit production of adipocytokines, in particular, adipocytokines
that elicit insulin resistance and to prevent onset of pathosis caused by
the insulin resistance, or improve the pathosis, the present invention
provides an agent or a food or drink which contains a compound having a
cyclolanostane skeleton, or an organic solvent extract, a hot water
extract of a plant of the family Liliaceae or Gramineae, or a fraction
thereof which contains the compound as an active ingredient.

Claims:

1. An agent for improving insulin resistance comprising a compound
represented by the following general formula (1) as an active ingredient:
##STR00010## wherein R1 represents an alkyl group, or an alkenyl group
containing 1 or 2 double bonds or a substituted alkyl or alkenyl group
containing 1 or 2 hydroxyl group and/or carbonyl group, which is straight
or branched chain having 6 to 8 carbon atoms, R2 and R3 each
independently represent a hydrogen atom or a methyl group, and R4 forms
C═O with a carbon atom constituting the ring or is a group
represented by any one of the following formulas) ##STR00011##

2. The agent for improving insulin resistance according to claim 1,
wherein R2 and R3 both are methyl groups, R4 is a hydroxyl group, and R1
is represented by any one of the following
formulas:--CH2--CH2--CH2--C(CH3)2--CH2--CH.-
sub.2--CHRa--C(CH3)2Rb(wherein Ra is any of hydrogen atom,
hydroxyl or methyl group, and Rb is hydrogen atom or hydroxyl
group)--CH2--CH2--CH(CH2CH3)--CH(CH3)2
--CH2--CH2--CHRc-C(CH3)═CH2 (wherein Rc is any of
hydrogen atom, hydroxyl or methyl
group)--CH2--CH2--C(═O)--C(CH3)═CH2
--CH2--CH2--C(═CH2)--CH(CH3)2
--CH2--CH2--CH═C(CH3)2
--CH2--CH═C(CH3)--CH(CH3)2
--CH2--CH2--C(═CHCH3)--CH(CH3).sub.2.

3. The agent for improving insulin resistance according to claim 2,
wherein the compound is 9,19-cyclolanostan-3-ol or
24-methylen-9,19-cyclolanostan-3-ol.

4. The agent for improving insulin resistance according to any one of
claims 1 to 3, which comprises at least 0.001% by mass of the compound.

5. An agent for improving insulin resistance, which comprises an organic
solvent extract or a hot water extract of a plant, or a fraction thereof
comprising a compound represented by the following general formula (1),
wherein the organic solvent extract, the hot water extract of the plant,
or the fraction thereof comprises a composition as an active ingredient
comprising at least 0.001% by mass of the compound represented by the
following general formula (1) ##STR00012## wherein R1 represents an alkyl
group, or an alkenyl group containing 1 or 2 double bonds or a
substituted alkyl or alkenyl group containing 1 or 2 hydroxyl group
and/or carbonyl group, which is straight or branched chain having 6 to 8
carbon atoms, R2 and R3 each independently represent a hydrogen atom or a
methyl group, and R4 forms C═O with a carbon atom constituting the
ring or is a group represented by any one of the following formulas
##STR00013##

6. The agent for improving insulin resistance according to claim 5,
wherein the plant is a plant of the family Liliaceae or Gramineae.

7. The agent for improving insulin resistance according to claim 5,
wherein R2 and R3 both are methyl groups, R4 is a hydroxyl group, and R1
is represented by any one of the following
formulas:--CH2--CH2--CH2--CH(CH3)2
--CH2--CH2--CHRa--C(CH3)2Rb(wherein Ra is any of
hydrogen atom, hydroxyl or methyl group, and Rb is hydrogen atom or
hydroxyl group)--CH2--CH2--CH(CH2CH3)--CH(CH3).s-
ub.2 --CH2--CH2--CHRc-C(CH3)═CH2 (wherein Rc is
any of hydrogen atom, hydroxyl or methyl
group)--CH2--CH2--C(═O)--C(CH3)═CH2
--CH2--CH2--C(═CH2)--CH(CH3)2
--CH2--CH2--CH═C(CH3)2
--CH2--CH═C(CH3)--CH(CH3)2
--CH2--CH2--C(═CHCH3)--CH(CH3).sub.2.

8. The agent for improving insulin resistance according to claim 7,
wherein the compound is 9,19-cyclolanostan-3-ol or
24-methylen-9,19-cyclolanostan-3-ol.

9. A food or drink comprising the agent for improving insulin resistance
according to any one of claims 1 to 3 and 5 to 8.

10. The food or drink according to claim 9, which comprises at least
0.0001% by mass of the compound represented by the general formula (1).

11. (canceled)

12. (canceled)

13. (canceled)

14. (canceled)

15. A method for improving insulin resistance, which comprises
administering a compound represented by the following general formula
(1), or an organic solvent extract, hot water extract of a plant, or a
fraction thereof which comprises at least 0.001% by mass of the compound,
to a subject whose insulin resistance is to be improved. ##STR00014##
wherein R1 represents an alkyl group, or an alkenyl group containing 1 or
2 double bonds or a substituted alkyl or alkenyl group containing 1 or 2
hydroxyl group and/or carbonyl group, which is straight or branched chain
having 6 to 8 carbon atoms, R2 and R3 each independently represent a
hydrogen atom or a methyl group, and R4 forms C═O with a carbon atom
constituting the ring or is a group represented by any one of the
following formulas ##STR00015##

16. The method according to claim 15, wherein the plant is a plant of the
family Liliaceae or Gramineae.

17. The method according to claim 15 or 16, wherein R2 and R3 both are
methyl groups, R4 is a hydroxyl group, and R1 is represented by any one
of the following
formulas:--CH2--CH2--CH2--CH(CH3)2
--CH2--CH2--CHRa--C(CH3)2Rb(wherein Ra is any of
hydrogen atom, hydroxyl or methyl group, and Rb is hydrogen atom or
hydroxyl group)--CH2--CH2--CH(CH2CH3)--CH(CH3).s-
ub.2 --CH2--CH2--CHRc-C(CH3)═CH2 (wherein Rc is
any of hydrogen atom, hydroxyl or methyl
group)--CH2--CH2--C(═O)--C(CH3)═CH2
--CH2--CH2--C(═CH2)--CH(CH3)2
--CH2--CH2--CH═C(CH3)2
--CH2--CH═C(CH3)--CH(CH3)2
--CH2--CH2--C(═CHCH3)--CH(CH3).sub.2.

18. The method according to claim 17, wherein the compound is
9,19-cyclolanostan-3-ol or 24-methylen-9,19-cyclolanostan-3-ol.

Description:

TECHNICAL FIELD

[0001]The present invention relates to an agent for improving insulin
resistance, which contains a compound having a cyclolanostane skeleton as
an active ingredient, and a food or drink containing the same. In
particular, the present invention relates to an agent for improving
insulin resistance, which has an effect of controlling production of
adipocytokines that are factors involved in onset and exacerbation of
pathosis in which the insulin resistance plays a role, such as free fatty
acid, plasminogen activator inhibitor, tumor necrosis factor, monocyte
chemoattractant protein-1 and resistin, and relates to a food or drink
containing the same.

BACKGROUND ART

[0002]Insulin is a kind of hormones produced by β cells in Langerhans
islets of pancreas, and plays an important role in maintaining
homeostasis of living body by affecting lipid metabolism and protein
metabolism as well as sugar metabolism via insulin receptors which are
present in target tissues of insulin such as skeletal muscles, liver and
fats. Examples of the effects of insulin in respective target tissues
include promotion of absorption of glucose from blood into muscle cells
and adipocytes, promotion of glycogen production in liver and muscle
tissues, inhibition of gluconeogenesis in liver, promotion of glucose
consumption and fatty acid synthesis in the adipocytes, and inhibition of
degradation of lipids.

[0003]The insulin resistance means a state that the cells, organs or
individuals require larger amounts of insulin than those typically
required in order to obtain respective effects of insulin, that is, a
state of impaired insulin effects where sensitivity to insulin is
decreased. From results of past epidemiologic investigations,
hypertension, diabetes, hyperlipidemia (hypertriglyceridemia and
hypo-HDL-cholesterolemia), obesity and the like are considered insulin
resistance-based pathosis. The insulin resistance causes insufficient
effects of insulin in the sugar metabolism, results in compensatory
hyperinsulinemia for maintaining blood sugar level, whereby hyperglycemia
and glucose intolerance occur and diabetes is promoted by exhaustion of
pancreatic β cells. Furthermore, the hyperinsulinemia enhances
activation of sympathetic nerves and promotes sodium absorption of kidney
to cause hypertension, and also induces postprandial hyperlipidemia and
hyperuricemia, an increase in plasminogen activator inhibitor-1 (PAI-1),
and the like.

[0004]Meanwhile, the insulin resistance induces abnormal lipid metabolism
caused by the insufficient effects of insulin, and free fatty acid (FFA)
released from adipocytes increases in liver to promote synthesis of
triglyceride (TG), resulting in hypertriglyceridemia. Furthermore,
activity of lipoprotein lipase (LPL) generally having high insulin
sensitivity is decreased in the insulin resistant state, so degradation
of TG is decreased and the hypertriglyceridemia is additionally
exacerbated. Furthermore, with exacerbation of diabetes, complications
such as retinopathy, nephropathy and gangrene caused by angiopathy occur
so that cardiac infarction and cerebral infarction that are
arteriosclerotic diseases exacerbate, and hypertension exacerbates
cardiovascular diseases. As described above, the insulin resistance is
considered to be significantly involved in exacerbation of complicated
pathosis (Non-patent Document 1).

[0005]In recent years, from results of analysis of organ-specific gene
expression, it was revealed that various physiologically active
substances are secreted from fat tissues, and the fat tissues thus has
been recognized to be not only energy storage tissues but also the
largest endocrine organ in a living body. Endocrine factors derived from
the fat tissues are generically called adipocytokines, and play important
roles in maintenance of homeostasis in metabolism. However, it is
considered that, in a case of obesity, that is, a state where fats are
accumulated, an excessive or a too small amount of adipocytokines are
produced and secreted, and the balance of the adipocytokines is
disrupted, resulting in the insulin resistance.

[0006]The adipocytokines are classified into two groups: one that enhances
insulin sensitivity; and one that elicits insulin resistance,
representative examples of the former group include adiponectin, leptin,
AMPK (AMP-dependent protein kinase) and the like. In particular, it has
been reported that the adiponectin has an effect of canceling insulin
resistance and an effect of inhibiting gluconeogenesis in liver
(Non-patent Document 2).

[0007]Meanwhile, examples of the adipocytokines that elicit insulin
resistance include tumor necrosis factor-α (TNF-α), monocyte
chemoattractant protein-1 (MCP-1) that is a kind of inflammatory
chemokine, and resistin in addition to the aforementioned FFA and PAI-1.
In particular, it has been reported that TNF-α has an effect of
eliciting the insulin resistance by inhibiting tyrosine phosphorylation
of an insulin receptor and IRS1 (insulin receptor substrate 1) in the
insulin signal transduction mechanism so that the effect of insulin is
attenuated. Furthermore, it has been reported that, in the insulin
resistant state, the MCP-1 level in a living body is increased and mRNA
of GLUT4 (glucose transporter-4) that is a glucose-transporting carrier,
PPARγ (peroxisome proliferator-activated receptor γ) that is
an intranuclear receptor, β3AR (β3-adrenergic receptor) that is
a kind of β type catecholamine receptor of an adipocyte, and aP2
(adipocyte fatty-acid-binding protein 2) that is a fatty-acid-binding
protein are reduced. Therefore, MCP-1 is considered to be a causative
agent of decreasing insulin sensitivity (Non-patent Documents 3, 4 and
5).

[0008]As agents for improving insulin resistance, biguanide agents that
inhibit gluconeogenesis mainly in liver, and thiazolidine derivatives
that improve the insulin sensitivity of muscles and fat tissues have been
developed. Those agents have already been permitted as diabetic
medicines, and also used for treatment of arteriosclerosis. The
thiazolidine derivatives as represented by troglitazone and pioglitazone
are each considered to act as a ligand for peroxisome
proliferator-activated receptor (PPAR) that is an intranuclear
receptor-type transcription factor to promote differentiation of
adipocytes, thereby improving insulin resistance.

[0009]In addition, an agent for improving insulin resistance containing
adiponectin or their genes as an active ingredient (Patent Document 1), a
preventive and/or therapeutic agent for diseases caused by insulin
resistance containing a substance having affinity to bombesin receptor
subtype 3 (BRS-3) as an active ingredient (Patent Document 2), a free
fatty acid (FFA) decreasing agent containing a pyrrole derivative as an
active ingredient (Patent Document 3) and the like have been disclosed as
the agents for improving insulin resistance. Furthermore, a composition
for improving insulin resistance containing acetic acid and an ion or
salt thereof as an active ingredient (Patent Document 4), an agent for
improving insulin resistance comprising a fatty oil containing particular
diglyceride and/or monoglyceride (Patent Document 5) and the like have
been disclosed as the agents containing a substance derived from a food
or drink as an active ingredient.

[0010]Plant sterols such as β-sitosterol, campesterol and
stigmasterol have been known to have a decreasing effect on blood
cholesterol by inhibition of absorption of cholesterol, and practical use
thereof has been attempted by adding them as a fat composition to edible
oil. Furthermore, an anti-obesity agent and a lipid metabolism-improving
agent containing a cholestenone compound as an active ingredient which is
synthesized by using plant sterols such as β-sitosterol and
campesterol as a starting material have been disclosed (Patent Documents
6 to 8, and Non-patent Document 6).

[0034]With use of the biguanide agent that is a conventional agent for
improving insulin resistance, gastrointestinal dysfunction or rarely
lactic acidosis may occur. Furthermore, a thiazolidine derivative that is
the same kind of the agent may sometimes cause severe side effects such
as fluid retention, increase in body weight and liver dysfunction, so use
thereof requires additional attention. Further, for the insulin
resistance in states other than diabetes or hyperglycemia, it has been
practically difficult to use antidiabetic agents. Under such
circumstances, a development of a functional material which is excellent
in safety, can be ingested on a daily basis, and can efficiently improve
insulin resistance with as little a pain as possible has been desired.

[0035]In view of the aforementioned problems, the inventors of the present
invention have studied mechanisms of lifestyle-related disease caused by
the insulin resistance, such as hypertension, diabetes, hyperlipidemia
(hypertriglyceridemia and hypo-HDL-cholesterolemia) and obesity, and have
studied an agent relating to prevention, improvement and the like of the
lifestyle-related diseases, that is, an agent for improving insulin
resistance. The inventors of the present invention made attention to
adipocytokines that are factors involved in onset and exacerbation of the
insulin resistance, and assiduously studied a novel functional material
capable of improving insulin resistance by controlling the aforementioned
factors. As a result, the inventors of the present invention found that
compounds having a cyclolanostane skeleton had an effect for controlling
production of adipocytokines such as free fatty acid, TNF-α, and
MCP-1 in particular, an efficient effect for decreasing production of
adipocytokines that elicits the insulin resistance, thereby the insulin
resistance is improved.

[0036]Regarding the aforementioned effects of the present invention,
Patent Document 9 described only preventive effect of the plant extract
on differentiation of cultured adipocytes, a synthesis route of a
cycloartane type triterpene derivative and a promotion effect of
ergosterol on secretion of adiponectin, and did not describe a promotion
effect of the cycloartane type triterpene or cycloartenol that is a
derivative thereof on secretion of adiponectin. In addition, it did not
describe and disclose that the improving effect of the active ingredient
of the present invention on insulin resistance at all.

[0037]In addition, the inventors of the present invention found that the
compound having a cyclolanostane skeleton directly improve the insulin
resistance without intervention of insulin secretion property or the
like, by investigating using an insulin tolerance test (insulin stress
test), in addition to the glucose clamp method, the steady state plasma
glucose (SSPG) method and the minimal model method which are conventional
methods of evaluating the insulin resistance.

[0038]Such an insulin tolerance test is not performed in the
aforementioned Patent Documents 1 to 5. The inventors of the present
invention found a more advantageous effect for improving insulin
resistance, without being affected by insulin secretion property, than
conventional effects for improving insulin resistance, and accomplished
the present invention.

[0039]An object of the present invention is to provide an agent for
improving insulin resistance, which contains a compound having the
cyclolanostane skeleton as an active ingredient. In addition, another
object of the present invention is to provide a physiologically
functional food or drink containing the agent for improving insulin
resistance, such as a food for specified health use.

[0040]First invention of the present application to solve the
aforementioned problems is an agent for improving insulin resistance
containing a compound represented by the following general formula (1) as
an active ingredient.

##STR00001##

[0041](In the formula, R1 represents an alkyl group, or an alkenyl group
containing 1 or 2 double bonds or a substituted alkyl or alkenyl group
containing 1 or 2 hydroxyl group and/or carbonyl group, which is straight
or branched chain having 6 to 8 carbon atoms, R2 and R3 each
independently represent a hydrogen atom or a methyl group, and R4 forms
C═O with a carbon atom constituting the ring or is a group
represented by any one of the following formulas.)

##STR00002##

[0042]In addition, the following (1) to (3) are preferred embodiments of
the present invention.

[0043]1) The aforementioned R1 is represented by any one of the following
formulas, the aforementioned R2 and R3 both are methyl groups, and the
aforementioned R4 is a hydroxyl group.

--CH2--CH2--CH2--CH(CH3)2

--CH2--CH2--CHRa--C(CH3)2Rb

[0044](wherein Ra is any of hydrogen atom, hydroxyl or methyl group, and
Rb is hydrogen atom or hydroxyl group)

--CH2--CH2--CH(CH2CH3)--CH(CH3)2

--CH2--CH2--CHRc-C(CH3)═CH2

[0045](wherein Rc is any of hydrogen atom, hydroxyl or methyl group)

--CH2--CH2--C(═O)--C(CH3)═CH2

--CH2--CH2--C(═CH2)--CH(CH3)2

--CH2--CH2--CH═C(CH3)2

--CH2--CH═C(CH3)--CH(CH3)2

--CH2--CH2--C(═CHCH3)--CH(CH3)2

[0046]2) The aforementioned compound according to 1) is
9,19-cyclolanostan-3-ol or 24-methylen-9,19-cyclolanostan-3-ol.

[0047]3) The aforementioned compound according to 1) or 2) is contained at
least 0.001% by mass.

[0048]Second invention of the present application to solve the
aforementioned problems is an agent for improving insulin resistance,
which contains an organic solvent extract or hot water extract of a plant
containing a compound represented by the following general formula (1),
or a fraction thereof as an active ingredient, wherein the organic
solvent extract or hot water extract of a plant or the fraction thereof
contains at least 0.001% by dry mass of a compound represented by the
following general formula (1).

##STR00003##

[0049](In the formula, R1 represents an alkyl group, or an alkenyl group
containing 1 or 2 double bonds or a substituted alkyl or alkenyl group
containing 1 or 2 hydroxyl group and/or carbonyl group, which is straight
or branched chain having 6 to 8 carbon atoms, R2 and R3 each
independently represent a hydrogen atom or a methyl group, and R4 forms
C═O with a carbon atom constituting the ring or is a group
represented by any one of the following formulas.)

##STR00004##

[0050]Furthermore, the following 4) to 6) are preferred embodiments of the
present invention.

[0051]4) The aforementioned plant is a Liliaceae or a Gramineae plant.

[0052]5) The aforementioned R1 is represented by any one of the following
formulas, the aforementioned R2 and R3 both are methyl groups, and the
aforementioned R4 is a hydroxyl group.

--CH2--CH2--CH2--CH(CH3)2

--CH2--CH2--CHRa--C(CH3)2Rb

[0053](wherein Ra is any of hydrogen atom, hydroxyl or methyl group, and
Rb is hydrogen atom or hydroxyl group)

--CH2--CH2--CH(CH2CH3)--CH(CH3)2

--CH2--CH2--CHRc-C(CH3)═CH2

[0054](wherein Rc is any of hydrogen atom, hydroxyl or methyl group)

--CH2--CH2--C(═O)--C(CH3)═CH2

--CH2--CH2--C(═CH2)--CH(CH3)2

--CH2--CH2--CH═C(CH3)2

--CH2--CH═C(CH3)--CH(CH3)2

--CH2--CH2--C(═CHCH3)--CH(CH3)2

[0055]6) The aforementioned compound according to 5) is
9,19-cyclolanostan-3-ol or 24-methylen-9,19-cyclolanostan-3-ol.

[0056]Third invention of the present application to solve the
aforementioned problems is a food or drink containing the agent for
improving insulin resistance according to the first or second invention.

[0057]In addition, the following 7) is a preferred embodiment of the
present invention.

[0058]7) The food or drink contains 0.0001% by dry mass or more of the
compound represented by the aforementioned general formula (1).

[0059]Fourth invention of the present application to solve the
aforementioned problems is a use of a compound represented by the
aforementioned general formula (1), or an organic solvent extract or hot
water extract of a plant containing at least 0.001% by dry mass of the
compound, or a fraction thereof, in the production of an agent for
improving insulin resistance.

[0060]Fifth invention of the present application to solve the
aforementioned problems is a method for improving insulin resistance,
which comprises administering a compound represented by the
aforementioned general formula (1), or an organic solvent extract or hot
water extract of a plant containing at least 0.001% by dry mass of the
compounds, or a fraction thereof, to a subject whose insulin resistance
is to be improved.

[0061]In the aforementioned use and method of the present invention, a
preferred embodiment of the compound represented by the aforementioned
general formula (1) is the same as that of the second invention of the
present invention.

[0062]The agent for improving insulin resistance of the present invention
and the food or drink containing the same can be safely administered or
ingested, and have preventive effects on lifestyle-related diseases which
is considered to be caused by the insulin resistance. Furthermore, the
active ingredient of the agent for improving insulin resistance of the
present invention can be produced easily from a plant of the family
Liliaceae such as Aloe vera (Aloe barbadensis Miller) that can be safely
ingested from an experiential viewpoint for food and is readily
available.

BRIEF DESCRIPTION OF THE DRAWING

[0063]FIG. 1 is a graph showing change in blood glucose level in an
insulin tolerance test.

BEST MODE FOR CARRYING OUT THE INVENTION

[0064]Hereafter, preferred embodiments of the present invention will be
explained in detail. However, the present invention is not limited to the
following preferred embodiments and can be freely modified within the
scope of the present invention. In addition, percentage as used herein
indicates mass unless otherwise specified.

[0065]The compound used as the active ingredient of the agent for
improving insulin resistance (hereinafter also referred to as "the agent
of the present invention") of the present invention include any compounds
and derivatives as long as these have the structure represented by the
aforementioned general formula (1), and the effect for improving insulin
resistance (hereinafter also referred to as "the compound of the present
invention")

[0066]It is most preferred that a purity of the compound of the present
invention used as the active ingredient of the agent for improving
insulin resistance of the present invention is 100%. However, the purity
can be appropriately set within a range where the agent has the effect of
improving insulin resistance.

[0067]Furthermore, the composition used as the active ingredient of the
agent for improving insulin resistance of the present invention
(hereinafter also referred to as "the composition of the present
invention") is an extract of a plant of the family Liliaceae or
Gramineae, or a fraction thereof containing at least 0.001% by dry mass,
preferably 0.01% by dry mass or more, and more preferably 0.1% by dry
mass or more of the aforementioned compound represented by the general
formula (1). The upper limit of the content of the compound of the
present invention is not particularly limited, and it may be, for
example, preferably 10% by mass, or 50% by mass, 70% by mass or 90% by
mass.

[0068]In the present invention, dry mass means a mass measured after a
compound is dried by the drying method defined by "Drying Loss Test" that
is a general test method as described in Japanese Pharmacopoeia, 14th
Revision (Mar. 30, 2001, the Ministry of Health, Labor and Welfare,
Ministerial Notification No. 111). For example, the mass of the compound
of the present invention can be determined in such a manner that: about 1
g of the compound of the present invention is measured off, and dried at
105° C. for 4 hours; and the resultant is cooled by standing in a
desiccator; and the mass of the compound is weighed with scales.

[0069]According to an embodiment, the agent for improving insulin
resistance of the present invention and the food or drink containing the
same contain a compound having the cyclolanostane skeleton which have the
effect for improving insulin resistance, as an active ingredient. The
cyclolanostane skeleton is a compound represented by the following
general formula (2).

##STR00005##

[0070]Specific examples of the compound having the cyclolanostane skeleton
include compounds represented by the aforementioned general formula (1).
The number of double bonds existing in the compound having the
cyclolanostane skeleton is not particularly limited. Further, the number
of double bonds existing in the ring is not particularly limited either.
When two or more double bonds exist, they may be conjugated. The agent
and food or drink of the present invention may contain two or more types
of the compounds of the present invention.

[0071]In the compound of the present invention of the aforementioned
general formula (1), R1 is an alkyl group or an alkenyl group containing
1 or 2 double bonds, which is straight or branched chain having 6 to 8
carbon atoms, or a substituted alkyl or alkenyl group in which one or two
hydrogen atoms of the alkyl or alkenyl group are substituted by hydroxyl
group and/or carbonyl group, R2 and R3 each independently are a hydrogen
atom or a methyl group, and R4 forms C═O with a carbon atom
constituting the ring or is a group represented by any one of the
following formulas.

##STR00006##

[0072]In the aforementioned general formula (1), R1 is preferably any one
of the groups represented by the following formulas.

--CH2--CH2--CH2--CH(CH3)2 (i)

--CH2--CH2--CHRa--C(CH3)2Rb (ii)

[0073](wherein Ra is any of hydrogen atom, hydroxyl or methyl group, and
Rb is hydrogen atom or hydroxyl group)

--CH2--CH2--CH(CH2CH3)--CH(CH3)2 (iii)

--CH2--CH2--CHRc-C(CH3)═CH2 (iv)

[0074](wherein Rc is any of hydrogen atom, hydroxyl or methyl group)

--CH2--CH2--C(═O)--C(CH3)═CH2 (v)

--CH2--CH2--C(═CH2)--CH(CH3)2 (vi)

--CH2--CH2--CH═C(CH3)2 (vii)

--CH2--CH═C(CH3)--CH(CH3)2 (viii)

--CH2--CH2--C(═CHCH3)--CH(CH3)2 (ix)

[0075]Further, in the aforementioned general formula (1), it is preferred
that R2 and R3 are both methyl groups, and the aforementioned R4 is a
hydroxyl group. The most preferred compounds as the aforementioned
compound are those represented by the following formulas,
9,19-cyclolanostan-3-ol (formula (3)) and
24-methylene-9,19-cyclolanostan-3-ol (formula(4))

##STR00007##

[0076]That is, 9,19-cyclolanostan-3-ol is a compound represented by the
aforementioned general formula (1) wherein and R3 are methyl groups, R4
is a hydroxyl group, and R1 is a group represented by the aforementioned
formula (i). Further, 24-methylene-9,19-cyclolanostan-3-ol is a compound
represented by the aforementioned general formula (1) wherein R2 and R3
are methyl groups, R4 is a hydroxyl group, and R1 is a group represented
by the aforementioned formula (vi).

[0077]The compound of the present invention may be cycloartenol (formula
(5)) or 24-methylcycloartanol (formula (7)). Both of these compounds are
compounds represented by the aforementioned general formula (1) wherein
R2 and R3 are methyl groups, R4 is a hydroxyl group, and R1 is a group
represented by the aforementioned formula (vii) in cycloartenol or a
group represented by the aforementioned formula (ii) (Ra═CH3,
Rb═H) in 24-methylcycloartanol.

[0078]The compound of the present invention can be chemically produced by
a known production method. For example, methods for producing
cycloartenol (formula (5)) and 24-methylenecycloartanol (trivial name of
24-methylene-9,19-cyclolanostan-3-ol) (formula (4)) have been disclosed
in Japanese Patent Laid-open No. 57-018617, and a method for producing
cycloartenol ferulate (formula (6)) from γ-oryzanol and a method
for synthesizing a compound using a hydrolysate thereof as a starting
material have been disclosed in Japanese Patent Laid-open No.
2003-277269. Further, when the R1 moiety of the general formula (1)
contains a double bond, various derivative compounds can be produced by
using a technique of converting the double bond portion into an aldehyde
by ozone decomposition reaction and binding a phosphonate to it, a
technique of adding hydrogen to a double bond portion, or a technique of
oxidizing the double bond portion with ozone to convert it to an aldehyde
or an acid. Further, the production methods are not limited to chemical
synthesis methods, and the compounds may be biologically produced by
using a microorganism or the like. Alternatively, they may be produced by
using enzymes derived from microorganisms.

##STR00008##

[0079]The agent for improving insulin resistance of the present invention
and a food or drink containing the same may contain one type or two or
more arbitrary types of the aforementioned compounds.

[0080]It is known that compounds having the cyclolanostane skeleton are
contained in plants of the families Liliaceae, Leguminosae, Gramineae,
Solanaceae, Musaceae and so forth (refer to Phytochemistry, U.S.A., 1977,
Vol. 16, pp. 140-141; Handbook of phytochemical constituents of GRAS
herbs and other economic plants, 1992, U.S.A., CRC Press; Hager's
Handbuch der Pharmazeutischen Praxis, Vols. 2-6, 1969-1979, Germany,
Springer-Verlag Berlin). Accordingly, the compounds can be produced by
extracting from these plants, a part thereof or homogenate thereof using
a method such as extraction with an organic solvent or extraction with
hot water, and concentrating them.

[0081]Specifically, examples of the plant belonging to the family
Liliaceae include plants belonging to the genus Aloe or Allium. Examples
of the plants of the genus Aloe include Aloe vera (Aloe barbadensis
Miller), Aloe ferox Miller, Aloe africana Miller, Aloe arborescen Miller
var. natalensis Berger, Aloe spicata Baker and so forth. In the
production of the compound of the present invention or a composition
containing the same, although the whole of the aforementioned plant may
be used, it is preferable to use mesophyll (clear gel portion) thereof.
Such a plant or a part thereof is disrupted by using a homogenizer or the
like and thereby liquefied, and the compound of the present invention or
a composition containing the same is extracted from the disruption
product by using an organic solvent or hot water. Examples of the organic
solvent include alcohols such as methanol, ethanol and butanol; esters
such as methyl acetate, ethyl acetate, propyl acetate and butyl acetate;
ketones such as acetone and methyl isobutyl ketone; ethers such as
diethyl ether and petroleum ether; hydrocarbons such as hexane,
cyclohexane, toluene and benzene; halogenated hydrocarbons such as carbon
tetrachloride, dichloromethane and chloroform; heterocyclic compounds
such as pyridine; glycols such as ethylene glycol; polyhydric alcohols
such as polyethylene glycol; nitrile solvents such as acetonitrile,
mixtures of these solvents and so forth. Furthermore, these solvents may
be anhydrous or hydrous. Among these solvents, ethyl acetate/butanol
mixture (3:1) and chloroform/methanol mixture (2:1) are preferred.

[0082]As the extraction method, a method used for usual extraction of a
plant component can be used. Usually used is, for example, a method of
refluxing 1 to 300 parts by mass of an organic solvent with 1 part by
mass of fresh plant or dried plant with heating at a temperature at or
below the boiling point of the solvent and stirring or shaking, or a
method of performing extraction by ultrasonication at room temperature.
By isolating insoluble matters from the extraction liquor using a
suitable method such as filtration or centrifugation, a crude extract can
be obtained.

[0083]The crude extract can be purified by various types of chromatography
such as normal or reverse phase silica gel column chromatography. When a
gradient of chloroform/methanol mixture is used in normal phase silica
gel column chromatography as an elution solvent, the compound of the
present invention is eluted with a mixing ratio of
chloroform:methanol=about 25:1. Further, when a hexane/ethyl acetate
mixture (4:1) is used in reverse phase silica gel column chromatography
as an elution solvent, the compound of the present invention is eluted in
a fraction eluted at an early stage. The obtained fraction can be further
purified by HPLC or the like.

[0084]Further, the compound used for the present invention may also be
produced by a chemical synthesis method or a biological or enzymatic
method using microorganisms, enzymes or the like.

[0085]Whether the compound or composition obtained as described above
actually contains the compound of the present invention can be confirmed
by, for example, mass spectrometry (MS), nuclear magnetic resonance (NMR)
spectroscopy or the like.

[0086]The compound of the present invention can be used as an active
ingredient of the agent for improving insulin resistance of the present
invention and a food or drink containing the same as it is. Further, an
organic solvent extract or a hot water extract of a plant containing the
compound of the present invention, or a fraction thereof (hereinafter
referred to as "extract etc.") may also be used as an active ingredient
of the agent for improving insulin resistance and a food or drink
containing the same. In addition, when the Aloe vera is used as a plant
of the family Liliaceae, it is preferred that total content of aloin and
aloe-emodin, which are contained a lot in leaf-skin of Aloe vera, is 5
ppm or less.

[0087]The aforementioned extract etc. to be contained in the agent for
improving insulin resistance preferably contains at least 0.001% by dry
mass, more preferably 0.01to 1% by dry mass, particularly preferably 0.05
to 1% by dry mass, of the compound of the present invention. Further, the
aforementioned extract etc. to be contained in a food or drink preferably
contains at least 0.0001% by dry mass, more preferably 0.001 to 1% by dry
mass, particularly preferably 0.005 to 1% by dry mass, of the compound of
the present invention. The aforementioned extract etc. may contain two or
more types of the compound of the present invention. Further, the
aforementioned extract etc. may be a solution, or can also be lyophilized
or spray-dried in a conventional manner and stored or used as powder.

[0088]As the agent for improving insulin resistance of the present
invention, the compound of the present invention or the composition
containing the same such as extract etc. per se, or those combined with a
pharmaceutically acceptable carrier can be orally or parenterally
administered to a mammal including human. In the agent of the present
invention, the compound of the present invention may be a
pharmaceutically acceptable salt. Examples of the pharmaceutically
acceptable salt include both metal salts (inorganic salts) and organic
salts including, for example, those listed in "Remington's Pharmaceutical
Sciences," 17th edition, p. 1418, 1985. Specific examples thereof
include, but not limited to, inorganic acid salts such as hydrochloride,
sulfate, phosphate, diphosphate and hydrobromate, and organic acid salts
such as malate, maleate, fumarate, tartarate, succinate, citrate,
acetate, lactate, methanesulfonate, p-toluenesulfonate, pamoate,
salicylate and stearate. Furthermore, the salt may be a salt with a metal
such as sodium, potassium, calcium, magnesium and aluminum or a salt with
an amino acid such as lysine. Furthermore, solvates such as hydrates of
the aforementioned compound or pharmaceutically acceptable salts thereof
also fall within the scope of the present invention.

[0089]Dosage form of the agent for improving insulin resistance of the
present invention is not particularly limited and can be suitably
selected depending on the therapeutic purpose. Specific examples thereof
include tablet, pill, powder, solution, suspension, emulsion, granules,
capsule, syrup, suppository, injection, ointment, patch, eye drop, nasal
drop and so forth. For the preparation, additives generally used in usual
agent for improving insulin resistance as pharmaceutical carriers such as
excipients, binders, disintegrating agents, lubricants, stabilizers,
flavoring agents, diluents, surfactants and solvents for injection and so
forth can be used. Further, so long as the effect of the present
invention is not degraded, the compound of the present invention, or the
extract etc. containing the same can be used in combination with other
agents having an effect for improving insulin resistance.

[0090]Although the amount of the compound of the present invention or the
extract etc. containing the same contained in the agent for improving
insulin resistance of the present invention is not particularly limited
and can be suitably selected, the amount may be, for example, at least
0.001% by mass, preferably 0.01 to 1% by mass, particularly preferably
0.05 to 1% by mass, in terms of the amount of the compound of the present
invention.

[0091]In the present invention, the effect of improving insulin resistance
(the effect of enhancing insulin sensitivity) means an effect for
preventing or improving various adverse effects on health caused by a
decrease in insulin sensitivity, such as lifestyle-related diseases.
Specifically, the agent of the present invention efficiently inhibits an
increase or production of adipocytokines that elicit insulin resistance,
such as plasminogen activator inhibitor (PAI-1), free fatty acid (FFA),
tumor necrosis factor (TNF-α), MCP-1 and resistin, and has an
effect on decreasing risks, prevention, improvement or treatment of the
diseases involved in the insulin resistance. Thus, the agent for
improving insulin resistance of the present invention can be defined as
an agent for enhancing insulin sensitivity or an agent for controlling
adipocytokines production, in particular, an agent for controlling
production of an adipocytokines that elicits insulin resistance.

[0092]There are methods for evaluating insulin resistance such as the
glucose clamp test, the steady state plasma glucose (SSPG) method, the
minimal model method, a method of evaluating the insulin resistance by
calculating homeostasis model assessment insulin resistance (HOMA-IR)
from fasting blood glucose level and blood insulin concentration, and the
insulin tolerance test. Any of the aforementioned methods can be used for
the evaluation of the insulin resistance, however, in the present
invention, it is preferred to use the insulin tolerance test using
animals, because the test does not affected by insulin secretion property
or the like, and thus the insulin sensitivity can be directly
investigated.

[0093]The compound of the present invention has an effect of increasing
insulin sensitivity, and thus can prevent or improve pathosis caused by
insulin resistance. Therefore, the compound can be used as an active
ingredient of the agent for improving insulin resistance or a food or
drink containing the same. In addition, the insulin sensitivity can also
be evaluated by measuring a decrease in blood glucose level after
administration of insulin.

[0094]The agent for improving insulin resistance of the present invention
can prevent, improve or treat various diseases, complications and the
like caused by insulin resistance, and can decrease the risks of those
diseases, complications and the like. Furthermore, the agent for
improving insulin resistance of the present invention can preferably be
used for a patient whose insulin resistance is more aggravated than that
of a healthy person In addition, insulin resistance generally means a
state where a fasting plasma insulin level is 10 to 15 μU/ml or more,
and a HOMA index is 1.73 or more.

[0095]Examples of the various diseases caused by insulin resistance
include hypertension, hyperlipidemia, diabetes, abnormal glucose
tolerance, arteriosclerosis, hyperinsulinemia and obesity. Examples of
the complications caused by the diseases include (a) cerebral stroke,
nephrosclerosis and renal failure caused by hypertension, (b)
arteriosclerosis and pancreatitis caused by hyperlipidemia, (c) diabetic
retinopathy, nephropathy, neuropathy and diabetic gangrene caused by
diabetes, and (d) cerebral stroke, cerebral infarction, cardiovascular
diseases such as angina pectoris and cardiac infarction, nephropathy such
as uremia, nephrosclerosis and renal failure caused by arteriosclerosis.
In addition, the inventors of the present invention have found that the
compound of the present invention has an effect of decreasing hemoglobin
A1c level and improving hyperglycemia (WO 2006/035525). It is preferred
that the diseases to which the agent for improving insulin resistance of
the present invention is applied are not accompanied with a state where
the hemoglobin A1c level is higher than that of a healthy person.

[0096]Furthermore, an agent of the present invention which has an effect
of improving insulin resistance is expected to have an effect of
inhibiting production and increase of adipocytokines which elicit insulin
resistance, such as TNF-α, MCP-1 and FFA. Therefore, the agent of
the present invention has an effect of preventing and/or improving the
diseases caused by the increase of the aforementioned adipocytokines
which include autoimmune diseases such as rheumatoid arthritis, Crohn's
disease, inflammatory diseases in various organs such as nephritis,
pancreatitis, hepatitis and pneumonitis, angiopathy, sepsis, cancer
cachexia. Thus, the agent for improving insulin resistance of the present
invention can preferably be used for a patient in which the production of
the adipocytokines is enhanced, in particular, a patient in which the
production of the adipocytokines that elicit the insulin resistance is
enhanced.

[0097]The administration time of the agent of the present invention is not
particularly limited and can be suitably selected according to the method
for treating an objective disease Furthermore, the administration route
is preferably determined depending on the dosage form, age, sex and other
conditions of patients, severity of symptoms of patients and so forth.
The dose of the agent of the present invention is suitably selected
depending on the dosing regimen, age, sex, severity of disease, other
conditions of patients and so forth. The amount of the compound of the
present invention as an active ingredient is usually selected from the
range of, preferably 0.001 to 50 mg/kg/day, more preferably 0.01 to 1
mg/kg/day, as a tentative dose. Further, when an extract etc. containing
the compound of the present invention is used, the dry weight of the
extract etc. is selected from the range of, preferably 0.1 to 1000
mg/kg/day, more preferably 1 to 100 mg/kg/day, as a tentative amount. In
any case, the dose can be ingested, in a day, once or several times as
divided portions.

[0098]The compound of the present invention or the composition containing
the same can be added to food or drink (a drink or a food) to produce a
food or drink having an effect of improving insulin resistance. The form
and property of the food or drink are not particularly limited so long as
the effect of the active ingredient is not degraded, and the food or
drink can be orally ingested, and it can be produced in a conventional
manner by using raw materials usually used for food or drink except that
the aforementioned active ingredient is added. Furthermore, the amount of
the compound of the present invention or the extract etc. containing the
same contained in the food or drink of the present invention is not
particularly limited and can be suitably selected. For example, the
compound of the present invention or the extract etc. containing the same
is contained in food or drink in an amount of at least 0.0001% by mass,
preferably 0.001 to 1% by mass, more preferably 0.005 to 1% by mass, in
terms of the amount of the compound of the present invention.

[0099]The food or drink of the present invention can be used for various
applications utilizing the effect of improving insulin resistance. For
example, it can be used as food or drink useful for decreasing or
eliminating risk factors of lifestyle-related diseases caused by insulin
resistance. Furthermore, the food or drink of the present invention can
prevent the diseases caused by insulin resistance, for example,
hypertension, hyperlipidemia, diabetes and the like and can decrease
risks of these diseases. Furthermore, the food or drink of the present
invention can prevent various complications caused by insulin resistance,
for example, cerebral stroke, nephrosclerosis and renal failure caused by
hypertension, arteriosclerosis, pancreatitis and the like caused by
hyperlipidemia, diabetic retinopathy, nephropathy, neuropathy and
diabetic gangrene caused by diabetes, cerebral stroke, cerebral
infarction, cardiovascular diseases such as angina pectoris and cardiac
infarction, nephropathy such as uremia, nephrosclerosis and renal failure
caused by arteriosclerosis, and can decrease risks of these diseases.

[0100]Furthermore, the food or drink of the present invention is expected
to have an effect of inhibiting production and increase of adipocytokines
that elicit insulin resistance, such as TNF-α, MCP-1 and FFA.
Therefore, the agent of the present invention has an effect of preventing
the diseases and decreasing risks of these diseases caused by the
increase of the aforementioned adipocytokines which include autoimmune
diseases such as rheumatoid arthritis, Crohn's disease, inflammatory
diseases in various organs such as nephritis, pancreatitis, hepatitis and
pneumonitis, angiopathy, sepsis, cancer cachexia. Thus, the food or drink
of the present invention can preferably be ingested by a patient in which
the production of the aforementioned adipocytokines is enhanced, in
particular, a patient in which the production of the adipocytokines that
elicit insulin resistance is enhanced.

[0101]The food or drink of the present invention is preferably marketed as
food or drink attached with an indication that the food or drink is used
for improving insulin resistance, for example, "food or drink containing
a compound having an effect of improving insulin resistance indicated as
`For improving insulin resistance`", "food or drink containing a plant
extract indicated as `For improving insulin resistance`", or "food or
drink containing Aloe vera extract indicated as `For improving insulin
resistance`" and the like. In addition, because the compound of the
present invention, and the composition containing the same have an effect
for improving insulin resistance, the indication of "improving insulin
resistance" is thus considered to have a meaning of "enhancing insulin
sensitivity". Therefore, the food or drink of the present invention can
be indicated as "For enhancing insulin sensitivity". In other words, the
indication of "For improving insulin resistance" may be replaced by the
indication of "For enhancing insulin sensitivity".

[0102]The wording used for such an indication as mentioned above is not
necessarily be limited to the expression "For improving insulin
resistance" or "For enhancing insulin sensitivity", and any other wording
expressing the effect for enhancing insulin sensitivity, or the effect
for preventing and improving insulin resistance of course falls within
the scope of the present invention. As such a wording, for example, an
indication based on various uses allowing consumers to recognize the
effect for improving insulin resistance or the effect for enhancing
insulin sensitivity is also possible. Examples include indication of
"Suitable for those who tend to be insulin resistance" and "Useful for
decrease or elimination of risk factors (risks) of lifestyle-related
diseases".

[0103]The aforementioned term "indication" includes all actions for
informing consumers the aforementioned use, and any indications reminding
or analogizing the aforementioned use fall within the scope of the
"indication" of the present invention regardless of purpose, content,
objective article, medium etc. of the indication. However, the indication
is preferably made with an expression that allows consumers to directly
recognize the aforementioned use. Specific examples include actions of
indicating the aforementioned use on goods or packages of goods relating
to the food or drink of the present invention, actions of assigning,
delivering, displaying for the purpose of assigning or delivering or
importing such goods or packages of goods indicated with the
aforementioned use, displaying or distributing advertisements, price
lists or business papers relating the goods with indicating the
aforementioned use, or providing information including those as contents
with indicating the aforementioned use by an electromagnetic method
(Internet etc.) and so forth. The indication is preferably an indication
approved by the administration etc. (for example, an indication in a form
based on an approval, which is qualified on the basis of any of various
legal systems provided by the administration), and it is particularly
preferably an indication on advertisement materials at the sales spots
such as packages, containers, catalogs, pamphlets and POPs, others
documents and so forth.

[0104]Examples of the indication further include indications as health
food, functional food, enteric nutritive food, food for special dietary
uses, food with nutrient function claims, quasi-drug and so forth as well
as indications approved by the Ministry of Health, Labor and Welfare, for
example, indications approved on the basis of the system of food for
specified health uses and similar systems. Examples of the latter include
indications as food for specified health uses, indications as food for
specified health uses with qualified health claims, indications of
influence on body structures and functions, indications of reduction of
disease risk claims and so forth, and more precisely, typical examples
include indications as food for specified health uses (especially
indications of use for health) provided in the enforcement regulations of
Health Promotion Law (Japan Ministry of Health, Labor and Welfare,
Ministerial ordinance No. 86, Apr. 30, 2003) and similar indications.

[0105]The present invention will be explained more specifically with
reference to the following examples. However, the scope of the present
invention is not limited to the following examples.

[0106]Preparation examples of compounds having the cyclolanostane skeleton
will be mentioned below.

[0108]To 8.0 g of γ-oryzanol (Oryza Oil & Chemical Co., Ltd.) was
added 250 ml of distilled water, 50 g of sodium hydroxide, 150 ml of
isopropanol, 150 ml of ethanol and 150 ml of methanol, and the mixture
was refluxed with heating for 2 hours by using a mantle heater After the
reaction, the reaction mixture was poured into 1300 ml of water, and the
produced white precipitates were isolated by suction filtration. To wash
off the remaining alkali, the residue obtained by the filtration was
suspended in 1000 ml of water, and then collected by suction filtration
again. This procedure was repeated twice, and the finally obtained
residue was lyophilized under reduced pressure to obtain 5.91 g of an
oryzanol hydrolysate. This hydrolysate was purified by HPLC to obtain
2435 mg of 9,19-cyclolanostan-3-ol and 1543 mg of
24-methylene-9,19-cyclolanostan-3-ol.

[0109]The obtained 9,19-cyclolanostan-3-ol was used to synthesize
cycloartenol. In an amount of 302 mg of 9,19-cyclolanostan-3-ol, 150 ml
of isopropanol and 1.0 g of powdery 5% palladium/carbon catalyst were
charged into a sealed autoclave, the internal atmosphere was replaced
with a nitrogen gas, and then a hydrogen gas was introduced with applying
3 kg/cm2 of pressure. The mixture was heated with stirring, and when
the temperature reached 50° C., the hydrogen pressure was adjusted
to 5 kg/cm2. With supplementing hydrogen for the absorbed hydrogen
to maintain the pressure, the reaction was allowed for 6 hours. The
reaction mixture was filtered to remove the catalyst, concentrated and
then purified by silica gel column chromatography (developing solvent:
100% chloroform) to obtain 275 mg of cycloartenol. 24-Methyl-cycloartanol
was synthesized by using 24-methylene-9,19-cyclolanostan-3-ol as a
starting material. In an amount of 78 mg of
24-methylene-9,19-cyclolanostan-3-ol, 150 ml of isopropanol and 1.0 g of
powdery 5% palladium/carbon catalyst were charged into a sealed
autoclave, the internal atmosphere was replaced with a nitrogen gas, and
then a hydrogen gas was introduced with applying 3 kg/cm2 of
pressure. Then, the mixture was heated with stirring, and when the
temperature reached 50° C., the hydrogen pressure was adjusted to
5 kg/cm2. With supplementing hydrogen for the absorbed hydrogen to
maintain the pressure of 5 kg/cm2, the reaction was allowed for 6
hours. The reaction mixture was filtered to remove the catalyst,
concentrated and then purified by silica gel column chromatography
(developing solvent: 100% chloroform) to obtain 69 mg of
24-methylcycloartanol.

[0110]Preparation examples of extracted compositions containing a compound
having the cyclolanostane skeleton using Aloe vera (Aloe barbadensis
Miller) belonging to Liliaceae plant as a starting material will be
described below.

Preparation Example 2

[0111]In an amount of 100 kg of hulled Aloe vera (Aloe barbadensis Miller)
was liquefied by using a homogenizer, added with 100 L of an ethyl
acetate ester/butanol mixture (3:1) and stirred. The mixture was left
overnight to separate the ethyl acetate ester/butanol mixture and the
aqueous layer, and the ethyl acetate ester/butanol mixture was recovered.
The extracted composition containing a compound having the cyclolanostane
skeleton, which was obtained by concentrating the ethyl acetate
ester/butanol mixture under reduced pressure, weighed 13.5 g. LC-MS
measurement of this composition revealed that the content of
9,19-cyclolanostan-3-ol was 10 mg, and the content of
24-methylene-9,19cyclolanostan-3-ol was 70 mg.

Preparation Example 3

[0112]In an amount of 1 kg of Aloe vera powder was added with 10 L of a
chloroform/methanol mixture (2:1) and immersed overnight in the mixture
at room temperature, and then the chloroform/methanol mixture was
recovered. The organic solvents were completely removed from this mixture
at 28° C. to obtain 83 g of a composition containing a compound
having the cyclolanostane skeleton. LC-MS measurement of this composition
revealed that the content of 9,19-cyclolanostan-3-ol was 25.8 mg, and the
content of 24-methylene-9,19-cyclolanostan-3-ol was 24 mg.

Example 1

[0113]This example was performed in order to evaluate a change in the
level of free fatty acid (FFA) in blood serum caused by an application of
the agent of the present invention for improving insulin resistance by
using AKR mice in which insulin resistance is induced by feeding with a
high-fat diet.

(1) Preparation of Samples

[0114]Each of 9,19-cyclolanostan-3-ol and
24-methylene-9,19-cyclolanostan-3-ol produced in Preparation Example 3
was dissolved in DMSO, and each concentration was adjusted to 1 μg/ml
with distilled water to thereby prepare Test Samples 1 and 2. In this
case, the final DMSO concentration was adjusted to 0.2%. Furthermore, a
solution without the test samples was prepared as a negative sample.

(2) Test Method

[0115]6-week-old male AKR mice (purchased from The Jackson Laboratory,
USA) were preliminarily fed with a high-fat diet (Research Diet, Inc.)
for 2 months to induce insulin resistance. These mice were divided into
groups, each consisting of 8 mice. Each of the groups of mice was orally
administered with 1 ml per 40 g of body weight (25 μg/kg of body
weight) of the Test Samples 1, 2 or the negative sample once a day
everyday with a sonde. On the 60th day from the initiation of the
administration of the samples, blood was collected from the mice under
fasting, and the level of the free fatty acid in serum was measured by
using NEFA C-test Wako (Wako Pure Chemical Industries, Ltd.).

(3) Results (Level of Free Fatty Acid in Blood)

[0116]Table 1 shows levels of free fatty acid in mice serum at 60th day
from the initiation of the administration. As compared with the group
administered with the negative sample, it was observed that the free
fatty acid levels tend to decrease to 81.1% in the group administered
with Test Samples 1 or 2. Therefore, it was revealed that the
administration of the agent for improving insulin resistance of the
present invention decreases systemic level of the free fatty acid and
thus exhibits a preventive effect on elicit of insulin resistance.

[0117]This example was performed in order to evaluate an effect of the
agent for improving insulin resistance of the present invention on
production quantities of TNF-α and MCP-1 in each cell of adipose
tissue by using AKR mice in which insulin resistance is induced by
feeding with a high-fat diet.

(1) Preparation of Samples

[0118]In Example 2, the same Test Samples 1, 2 and the negative sample as
those prepared in Example 1 were used.

(2) Test Method 6-week-old male AKR mice (purchased from The Jackson
Laboratory, USA) were preliminarily fed with a high-fat diet (Research
Diet, Inc.) for 2 months to induce insulin resistance. These mice were
divided into groups, each consisting of 8 mice. Each of the groups of
mice was orally administered with 1 ml per 40 g of body weight (25
μg/kg of body weight) of the Test Sample 1, 2 or the negative sample
once a day everyday with a sonde. On the 60th day from the initiation of
the administration of the samples, epididymal fats tissues were collected
from the mice under fasting, and 1 g of each of the fats was added with
1.5 ml of D-MEM/F12 medium containing 0.5% bovine serum albumin, followed
by culturing at 37° C. After 1 hour of the culture, culture
supernatants were collected, and concentrations of TNF-α and MCP-1
in the culture supernatants were measured by ELISA method (Biosource).

(3) Results (Production Quantities of TNF-α and MCP-1)

[0119]Table 2 shows production quantities of TNF-α of adipose
tissues. Table 3 shows production quantities of MCP-1 of adipose tissues.
As apparent from these results, significant inhibitory effects on the
production of both of TNF-α and MCP-1 was observed in the group
administered with the Test Sample 1 or 2 as compared with the group
administered with the negative sample. From the results of the present
example, it was revealed that the administration of the agent for
improving insulin resistance of the present invention decreases the
production of adipocytokines in the fat tissues that exacerbate the
insulin resistance, and prevent the elicit of the insulin resistance. In
addition, p values in the tables indicate significance probability by
Tukey-Kramer's test.

[0120]This example was performed in order to evaluate an enhancing effect
of the agent for improving insulin resistance of the present invention on
insulin sensitivity by performing an insulin tolerance test using AKR
mice in which insulin resistance is induced by feeding with a high-fat
diet.

(1) Preparation of Samples

[0121]In Example 3, the same Test Samples 1, 2 and the negative sample as
those prepared in Examples 1 and 2 were used.

(2) Test Method 6-week-old male AKR mice (purchased from The Jackson
Laboratory, USA) were preliminarily fed with a high-fat diet (Research
Diet, Inc.) for 2 months to induce insulin resistance. These mice were
divided into groups, each consisting of 8 mice. Each of the groups of
mice was orally administered with 1 ml per 40 g of body weight (25
μg/kg of body weight) of the Test Samples 1, 2 or the negative sample
once a day everyday with a sonde. On the 45th day from the initiation of
the administration of the samples, an insulin tolerance test was
performed. In the present example, the insulin tolerance test was
performed in such a manner that: the mice were fasted for 4 hours, and
were then intraperitoneally administered with 0.75 U/Kg of body weight of
a human insulin (Eli Lily and Company); and changes with time in blood
glucose level were measured from the initiation of the administration of
the insulin to after 60 minutes later.

(3) Results (Insulin Tolerance Test)

[0122]The results of the present example were as shown in FIG. 1. FIG. 1
shows the results of the insulin tolerance test. As apparent from FIG. 1,
rapid decrease in blood glucose levels immediately after the initiation
of the insulin was observed in the group administered with the Test
Sample 1 or 2, while no decrease in blood glucose level was observed for
15 minutes after the initiation of the administration of insulin in the
group administered with the negative sample. From the results of the
present example, it was revealed that the administration of the agent for
improving insulin resistance of the present invention enhances the
insulin sensitivity.

INDUSTRIAL APPLICABILITY

[0123]The present invention can provide an agent for improving insulin
resistance which is safe without side effects and is capable of enhancing
insulin sensitivity, and can provide a physiologically functional food or
drink such as foods for specified health use containing the agent for
improving insulin resistance. The agent for improving insulin resistance
and the physiologically functional food or drink containing the same of
the present invention have improving or preventive effects on diseases,
complications and the like caused by a decrease insulin sensitivity, for
example the lifestyle-related diseases such as hypertension, diabetes,
hyperlipidemia and arteriosclerosis, and have decreasing effects on risks
of those diseases, complications and the like.